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Subject: Re: [PATCH v2 1/2] Bluetooth: btusb: Indicate Microsoft vendor
 extension for Intel 9460/9560 and 9160/9260
From:   Marcel Holtmann <marcel@holtmann.org>
In-Reply-To: <CABmPvSFwb1zu33fUog9hVK6y2R=PmKeGyOwkP3+=ZzE_qkX9yQ@mail.gmail.com>
Date:   Thu, 26 Mar 2020 07:12:52 +0100
Cc:     Bluetooth Kernel Mailing List <linux-bluetooth@vger.kernel.org>,
        Luiz Augusto von Dentz <luiz.von.dentz@intel.com>,
        Alain Michaud <alainm@chromium.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        netdev <netdev@vger.kernel.org>
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Message-Id: <B8FE9D19-4589-47C6-9C1F-2DC1146F53DA@holtmann.org>
References: <20200325070336.1097-1-mcchou@chromium.org>
 <20200325000332.v2.1.I0e975833a6789e8acc74be7756cd54afde6ba98c@changeid>
 <72699110-843A-4382-8FF1-20C5D4D557A2@holtmann.org>
 <CABmPvSFL_bkrZQJkAzUMck_bAY5aBZkL=5HGV_Syv2QRYfRLfw@mail.gmail.com>
 <B2A2CFFE-8FC1-462B-9C7F-1CD584B6EB24@holtmann.org>
 <CABmPvSFwb1zu33fUog9hVK6y2R=PmKeGyOwkP3+=ZzE_qkX9yQ@mail.gmail.com>
To:     Miao-chen Chou <mcchou@chromium.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi Miao-chen,

>>>>> This adds a bit mask of driver_info for Microsoft vendor extension and
>>>>> indicates the support for Intel 9460/9560 and 9160/9260. See
>>>>> https://docs.microsoft.com/en-us/windows-hardware/drivers/bluetooth/
>>>>> microsoft-defined-bluetooth-hci-commands-and-events for more information
>>>>> about the extension. This was verified with Intel ThunderPeak BT controller
>>>>> where msft_vnd_ext_opcode is 0xFC1E.
>>>>> 
>>>>> Signed-off-by: Miao-chen Chou <mcchou@chromium.org>
>>>>> ---
>>>>> 
>>>>> Changes in v2:
>>>>> - Define struct msft_vnd_ext and add a field of this type to struct
>>>>> hci_dev to facilitate the support of Microsoft vendor extension.
>>>>> 
>>>>> drivers/bluetooth/btusb.c        | 14 ++++++++++++--
>>>>> include/net/bluetooth/hci_core.h |  6 ++++++
>>>>> 2 files changed, 18 insertions(+), 2 deletions(-)
>>>>> 
>>>>> diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
>>>>> index 3bdec42c9612..4c49f394f174 100644
>>>>> --- a/drivers/bluetooth/btusb.c
>>>>> +++ b/drivers/bluetooth/btusb.c
>>>>> @@ -58,6 +58,7 @@ static struct usb_driver btusb_driver;
>>>>> #define BTUSB_CW6622          0x100000
>>>>> #define BTUSB_MEDIATEK                0x200000
>>>>> #define BTUSB_WIDEBAND_SPEECH 0x400000
>>>>> +#define BTUSB_MSFT_VND_EXT   0x800000
>>>>> 
>>>>> static const struct usb_device_id btusb_table[] = {
>>>>>     /* Generic Bluetooth USB device */
>>>>> @@ -335,7 +336,8 @@ static const struct usb_device_id blacklist_table[] = {
>>>>> 
>>>>>     /* Intel Bluetooth devices */
>>>>>     { USB_DEVICE(0x8087, 0x0025), .driver_info = BTUSB_INTEL_NEW |
>>>>> -                                                  BTUSB_WIDEBAND_SPEECH },
>>>>> +                                                  BTUSB_WIDEBAND_SPEECH |
>>>>> +                                                  BTUSB_MSFT_VND_EXT },
>>>>>     { USB_DEVICE(0x8087, 0x0026), .driver_info = BTUSB_INTEL_NEW |
>>>>>                                                  BTUSB_WIDEBAND_SPEECH },
>>>>>     { USB_DEVICE(0x8087, 0x0029), .driver_info = BTUSB_INTEL_NEW |
>>>>> @@ -348,7 +350,8 @@ static const struct usb_device_id blacklist_table[] = {
>>>>>     { USB_DEVICE(0x8087, 0x0aa7), .driver_info = BTUSB_INTEL |
>>>>>                                                  BTUSB_WIDEBAND_SPEECH },
>>>>>     { USB_DEVICE(0x8087, 0x0aaa), .driver_info = BTUSB_INTEL_NEW |
>>>>> -                                                  BTUSB_WIDEBAND_SPEECH },
>>>>> +                                                  BTUSB_WIDEBAND_SPEECH |
>>>>> +                                                  BTUSB_MSFT_VND_EXT },
>>>>> 
>>>>>     /* Other Intel Bluetooth devices */
>>>>>     { USB_VENDOR_AND_INTERFACE_INFO(0x8087, 0xe0, 0x01, 0x01),
>>>>> @@ -3734,6 +3737,8 @@ static int btusb_probe(struct usb_interface *intf,
>>>>>     hdev->send   = btusb_send_frame;
>>>>>     hdev->notify = btusb_notify;
>>>>> 
>>>>> +     hdev->msft_ext.opcode = HCI_OP_NOP;
>>>>> +
>>>> 
>>>> do this in the hci_alloc_dev procedure for every driver. This doesn’t belong in the driver.
>>> Thanks for the note, I will address this.
>>>> 
>>>>> #ifdef CONFIG_PM
>>>>>     err = btusb_config_oob_wake(hdev);
>>>>>     if (err)
>>>>> @@ -3800,6 +3805,11 @@ static int btusb_probe(struct usb_interface *intf,
>>>>>             set_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks);
>>>>>             set_bit(HCI_QUIRK_SIMULTANEOUS_DISCOVERY, &hdev->quirks);
>>>>>             set_bit(HCI_QUIRK_NON_PERSISTENT_DIAG, &hdev->quirks);
>>>>> +
>>>>> +             if (id->driver_info & BTUSB_MSFT_VND_EXT &&
>>>>> +                     (id->idProduct == 0x0025 || id->idProduct == 0x0aaa)) {
>>>> 
>>>> Please scrap this extra check. You already selected out the PID with the blacklist_table. In addition, I do not want to add a PID in two places in the driver.
>>> If we scrap the check around idProduct, how do we tell two controllers
>>> apart if they use different opcode for Microsoft vendor extension?
>> 
>> for Intel controllers this is highly unlikely. If we really decide to change the opcode in newer firmware versions, we then deal with it at that point.
>> 
>> However for Intel controllers I have the feeling that we better do it after the Read the Intel version information and then do it based on hardware revision and firmware version.
> I would agree with you given that the FW loaded for the same HW can
> differ, and different FW version may have different configuration in
> terms of the use of extensions. But it's not clear to me how we can
> tell whether an extension is supported based on a version number. Is
> there any implication on the support of an extension given a FW
> version (e.g. any FW version greater than 10 would support MSFT
> extension)?

that is for us to figure out. I will get back to you on that.

Regards

Marcel